Fuel oil spills resulting from storage tank leaks, overfills or catastrophic floods pose a sizable risk to human health. Hydrocarbons get entrapped along with water inside the pore spaces of solids thus forming so called “ganglia.” This problem emerged after a catastrophic flood that occurred in Grand Forks, N. Dak. in April 1997. During the flood, a number of fuel oil tanks in residential basements were ruptured, and the spilled hydrocarbons mixed with water and absorbed in concrete walls. Afterward, slow evaporation exposed residents to hydrocarbon vapors for years. Unfortunately, common remediation techniques, such as heating and pump-and-treat technologies, prove to be inefficient. For instance, heating caused pollutants to penetrate deeper within concrete blocks, which merely effected a delay in the release of hydrocarbon vapors into the ambient air. Treating surfaces with soap did not work, because surfactants could not reach the oil trapped in the ganglia.
Most of the research on bioremediation of solids addresses the biodegradation of hydrocarbons in soils. Some research describes the removal of hydrocarbons from other low-porosity solid media, such as sand or metal filings. The feasibility of biotreatment has been postulated for construction debris. Concrete bioremediation has been thoroughly documented only for organochlorine herbicides in stirring reactors suitable only for application on concrete debris. Therefore, there is a need for an efficient method of removing hydrocarbons from the pore spaces of solids.